EP0894354B1 - Electric cable connection - Google Patents

Abstract

An electric cable connection for a single or multi-core power and control cable, in which the electrically insulating and sealing coating consists of a cast resin or shrink sleeve (12, 9) and in which the cores (8) in the region of the connector (5) are surrounded by a dimensionally stable coating (2), covered in turn by an outer sleeve covering the core insulation (1) and in which, besides the electrically insulating and damp-proofing protection, there is over each electric core connection, and electrically insulating, damp-repellent, high-temperature and thus fire-resistant moulding (2) remaining dimensionally stable under the action of heat as a casing for each individual core connection (8, 5) permanently spaced apart by heat-resistant spacers, where the dimensionally stable moulding (2) advantageously consists of a fireproof ceramic or a high-temperature-resistant quartz glass or quartz substance.

Description

The invention relates to an electrical cable connection for single or multi-core power and control cables, at which is the electrically insulating and sealing covering in a known manner using a cast resin or Shrink sleeve is made. With such a cable connection (DE 35 33 375 C2) it is known to veins in the area the connector with a dimensionally stable position from one to surround inorganic and / or ceramic fiber material and this with a covering of the wire insulation To enclose shrink tubing. The layer of fiber material should be resistant to fire and can be made from one Wraps or a modeled body consist.

With such cable connections in the event of fire essentially dimensionally stable layers are preserved and closed Prevent short-circuits from touching the veins, if the plastic components of the cable connection already have melted or burned. The danger of this harmful Touching the wires results from thermal mechanical changes occurring due to length changes Forces and can be reduced if the cable wires by known devices (DE 90 04 349 U1) in their positions secured at a distance from each other.

Cable connections of this type have high thermal loads however not sufficient resilience and functionality shown.

Cable connections have also become known in which Shrink sleeves made of a self-extinguishing material a certain level of fire protection. This too can, however, withstand high thermal loads in the event of a fire do not resist; they burn after a period of time Flame load completely and then ensure functionality the cable connection no longer. Also known Cast resin molding materials with additives for self-extinguishing only show limited effectiveness in the event of a fire and are not suitable for the high requirements, as in the relevant standards IEC 331 or DIN 4102 Part 12 are required to be met.

These plastics are predominantly made with a halogen-containing one Flame retardants and diantimony trioxide as synergists equipped. It is also a plastic equipment with halogen-free flame retardants, e.g. Hydroxides or also known as phosphorus compounds. Through this Systems can connect the flame resistance of the cables with other flame-resistant materials such as mica wraps etc. on the single wires, for a sufficient Period can be reached.

The high demands on fire protection and functionality to the cables or the cable connections that especially in public buildings and parts of buildings, such as. Elevator shafts, or also required on oil platforms require a special design of the cable connections. This keeps the insulation (FE) or function maintenance (E) of the cable connections, depending from the respective local conditions of at least Ensure 30 to 180 minutes.

Also a cable connection according to DE 35 cited at the beginning 33 375 C2, at the refractory fiber material under the Shrink tube of the wire connection is arranged, fulfilled because of the occurring high thermal and mechanical Loads in the event of fire the required functionality not reliable.

Solutions with heavily filled protective wraps are also known, which is disadvantageous that this under the heat to sinter. This creates a fireproof, however porous layer. Despite the good thermal resistance This layer has the disadvantage that the forming moisture from the combustible components of the Cable or the cable connection diffuses into this porous layer, and that this creates conductive paths between the Single wires or one or more wires and the earth potential are formed, which can lead to short circuits.

Furthermore, it has been shown that under the effect of the strong mechanical forces due to the effects of heat in the event of fire despite the use of spacing devices move the single wire connections against each other or so pressed the layers of the fiber material that can be a reliable electrical connection cannot be ensured without short circuits.

Another significant disadvantage of this known cable connection can still be seen in the fact that the assemblies are very cumbersome and are time consuming. Both the individual Wrap around the single wire connections and also the whole Cable connection especially require those that occur frequently complicated installation situations on site Level of care and therefore time required to ensure a safe and establish reliable cable connection. Are common the cable support elements in places that are difficult to access, e.g. directly under the ceiling or in corners of a room and the fitter then has to do the various steps run in very cramped conditions. Especially that Application of flame protection coils made of fire-resistant fiber material on the wire connections turns out to be complicated there is a sufficiently large free assembly space this is necessary, a prerequisite to such Places can often not be made possible.

The object of the invention is derived from these facts to create a cable connection that both the high fire safety requirements for public Buildings and similar systems are fully sufficient and at the same time simple and safe assembly allowed. Are there to meet the basic requirements that the individual wire connections against high thermal loads, as in Fire trap occur, be reliably protected. To the individual wire connections with suitable fire-resistant Molded parts secured against each other so that the in the event of fire due to the thermal decomposition of the counter Insulates moisture and ensures mechanical stability Components released fire products, mainly consisting of water vapor and other conductive gases, conductive contacts, especially short circuits between the individual conductors can be reliably avoided. Thereby is achieved that the cable connection also under direct Exposure to fire for a considerable period of time reached.

This can result in a considerable intact operating time of the Cable connection even under the influence of very high temperatures achieved in the event of a fire with a maximum of safety become. This is according to the teaching of the invention achieved that the single wire connections not only be insulated from each other against moisture, but additionally with a highly fire-resistant and no moisture receiving molding are protected. You can these cable connections both in cast resin as well be manufactured using shrink technology.

The above requirements are met by the Cable connection according to the invention fulfilled, starting from from the described prior art - above everyone electrical wire connection next to the electrical and against Moisture insulating protection an electrically insulating, moisture-repellent, high-temperature and therefore fire-resistant molded body that remains dimensionally stable in the heat as a covering of the individual, through heat-resistant Spacers arranged permanently spaced wire connections is.

Spacers as such are known, for example through DE 90 04 349 U1. The well-known spacers are mostly injection molded parts made of non-heat or flame resistant Plastics.

Cable connections that provide protection against thermal loads have, in addition to the patent mentioned above also known from other publications become.

In known cable connections are in a fire due to the high thermal stresses at the same time mechanical forces can act, the cable jackets and the wire insulation as well as the heat shrink tubing and Cast resin molding materials burned and deformed, so that it between the veins on the one hand as well as between one or several wires and the environment, the earth potential quite Short circuits can quickly occur, so that the function the cable connection is no longer ensured.

In many cases, this also applies to cable connections where Shrink sleeves made of a self-extinguishing material used for insulation and a certain fire protection become. However, these can also withstand the high thermal stresses do not resist effectively in the event of fire; she burn after a certain time under the flame load and then ensure the functionality of the cable connection no more. The plastics and whose equipment with flame retardant materials are in the Technical literature, and also in DE 14 94 922 A1 and DE 15 69 123 A1.

Cast resin molding materials are also used as an insulating material with additives known for self-extinguishing, which however - as mentioned - show limited stability in the event of fire, and which are not suitable to meet the requirements, such as these in the relevant standards IEC 331 or DIN 4102 Part 12 are set.

The ones to be used for the cable connections according to the invention Plastics must contain a flame retardant containing halogen and diantimony trioxide as synergists his. The plastics can also be equipped with halogen-free ones Flame retardants, e.g. Hydroxides or phosphorus compounds also serve this purpose. By these systems are related to the flame resistance of the cables with other flame-resistant materials such as mica wraps etc. on the single wires, for a sufficient Period reached.

Also the embodiment mentioned above in relation to the prior art DE 35 33 375 C2 - corresponding to EP 0 216 613 A2 - does not meet the requirements because that too there used refractory fiber material under the shrink tube because of its fiber structure stronger flame loads cannot withstand, as practical tests show have because of the thermal and mechanical stresses has not grown.

They are also wire connections with heavily filled protective coils known; these have the major disadvantage that the protective wraps sinter due to the fire load, to form a refractory porous layer. This layer shows a certain thermal resistance, shows but at the same time the tendency to the moisture that forms from the flammable components of the cable or Store cable connection in this layer and thus conductive paths between the single wires or one or multiple wires and the earth potential to form, resulting in short circuits can lead.

GB 2 295 501 A is still a high-voltage cable connection with a cast resin sleeve, in which surround the connectors of the single wires with a mastic filling, which are covered with a shrink sleeve (RAYVOLVE) is. The single cable connections are by means of spacers fixed against each other, and within the cast resin sleeve is a rigid insulating sleeve with a wall thickness from 3 to 10 mm from a polymer such as PE or PVC, Acrylic or other polymer.

Resistance or Functionality in the event of fire is not expected, which is why this writing can be disregarded here.

Other disadvantages of the known cable connections are still to see that their assembly is cumbersome and therefore is time consuming. Both the individual wraps around the single wire connections and also the entire cable connection have to be installed on site even in confusing installation positions can be installed safely and reliably. Are common the cable support elements are difficult to access Locations, e.g. directly under the ceiling or in corners of a Room and the fitter must then complete the various work steps perform in very confined spaces. Especially the application of flame retardants a fire-resistant fiber material on the wire connections turns out to be difficult because it takes up a lot of space is necessary for this than is often available.

The invention addresses these difficulties by Creation of a cable connection that meets both the high fire safety requirements for public buildings and similar systems fully sufficient and at the same time a simple and also safe assembly allowed.

Cast resin technology:

For the assembly of a cast resin connection sleeve, the Carefully strip the ends of the cables to be connected and after removing the cable assembly elements, the single wires exposed and prepared for the application of the connectors. About the individual wires of a cable insulating molded bodies made of fire-resistant material pushed on and then the ends of the single wires in conventional technology with press or screw connectors electrically connected to each other. About these junctions then the fire-resistant moldings pushed and the spaces between the molded parts and the wire insulation with a cement or sealant sealed that penetration of the casting resin when casting is reliably prevented. Are all wire connections produced in the manner described, then in an advantageous design of the cable connection itself known spacers, but from a non-burning or flammable and therefore thermally stable material, which does not absorb moisture, for spacing the moldings are used over the wire connections. Spacers are elongated molded parts of multi-pointed star-shaped or a multiple U-profile-like shape and preferably extend along the cable axes on both sides beyond the single wire connections. Subsequently the molded shells of the cast resin set in Mounted and on the usual way over the cable connection attached to the cable jacket. The sealing of the molded shells on the cable jackets is also done in a well known manner Wise. Then the curable insulating molding material prepared according to the manufacturer's instructions and poured into the molded bowl. After curing the Cast resin is the cable connection both mechanically and also electrically resilient, and fire resistance is ensured over a longer period.

Shrinking technique:

The cable ends are like for the casting resin technology for the Connect prepared. The difference is here in that the single wires are not just fire-resistant Molded body, but also a heat shrink tube in the so-called parking position is brought. after the electrical wire connection in the usual way by means of connectors is produced, the heat shrink tubing is called electrically insulating and moisture-proof Enclosure pushed over the connector and by means of a Heat source, hot air or flame, shrunk onto the connector. The heat shrink tubing is dimensioned so that that after shrinking on both sides except for the respective wire insulation is sufficient. Then the fire-resistant molded body positioned over the shrink tube and if necessary with suitable means, e.g. fixed with a piece of insulating tape. In an advantageous Training of the cable connection can also be done via a layer of mica tape on the shrink tube of the wire connections be wrapped.

When the splice, the entirety of the wire connections, is made is the single wire connections with a fire-resistant spacers in the manner described above spaced and then fixed over the splice another shrink tube shrunk that sized is that he is on both sides except for the cable jackets enough. Another advantageous embodiment of the cable connection is that an extra over the splice fire-resistant molded part pushed and fixed before the outer shrink tube is shrunk. This additional fire-resistant molded part is dimensioned that the splice completely covers on both sides is. After cooling the fire-resistant according to the invention This is mechanical and at room temperature fully electrically loadable.

The fire-resistant molded parts used for the insulation of single wire connections and tools for the Spacing of these consist of an electrically insulating, no moisture absorbing high temperature resistant and thermally stable material, preferably made of a refractory ceramic or a high temperature resistant one Quartz glass or quartz.

In the cable connections made using shrink technology shrink sleeves are preferred equipped with a flame retardant.

Another advantage arises when the inner sleeves not directly one above the other, but offset in the longitudinal axis to be ordered.

Because the inner sleeves individually against each other and additionally overall not only electrically insulating and sealed against moisture but also against fire are reliably estimated at the same time great resilience of the entire cable connection against fire exposure. So could the test criteria of high fire exposure for public Buildings over 90 minutes at 1000 ° C (functional integrity) as well as for e.g. Oil platforms over 180 minutes at 750 ° C (Insulation preservation) for the cable connection.

With the use of the cable connections according to the invention can be used for the complete replacement of already laid cables for building extensions or repairs for mechanical Damage can be dispensed with without preserving the insulation or the functionality of existing systems is impaired becomes. This makes it significant at the same time Material savings achieved and the cost of maintenance lowered.

The individually necessary work steps in production the cable connection according to the invention are relatively simple even in poorly accessible places and in confined spaces executable so that the assembly compared to the previous one Technology not only much easier, but ultimately also becomes safer.

Through the use of precisely dimensioned according to the invention insulating and sealing shrink sleeves as well the molded parts made of fire-resistant materials or Aids for spacing the inner sleeves from likewise refractory materials in relatively small dimensions the finished cable connection using shrink technology slim design, easy to manufacture and also easy Can be dismantled in densely populated cable trays.

The cable connections made in this way in shrink as well Cast resin technology is both electrically safe and mechanical and against high thermal loads in one Fire estimated.

Fig. 1

eine für die Montage vorbereitete und teilweise montierte Einzeladerverbindungen der Kabelverbindung in Giessharztechnik;

Fig. 2

in Teil-Schnittdarstellung eine Innenmuffe über den Verbinder einer Einzelader für eine Giessharz-Formschale;

Fig. 3

eine fertig montierte Kabelverbindung mit vier Einzeladern in einer Giessharz-Formschale für das Vergiessen mit einem aushärtbaren Isolierstoff;

Fig. 4

eine für die Montage in Schrumpftechnik vorbereitete und teil-montierte Verbindung von drei Einzeladern;

Fig. 5

in Teilschnitt-Darstellung die Einzelheiten einer Innenmuffe über den Verbinder einer Einzelader für eine Schrumpfmuffe;

Fig. 6

im Teilschnitt eine Kabelverbindung mit mehreren Einzeladern als fertig geschrumpfte und betriebsbereite Schrumpfmuffe.

Embodiments of the invention and their special features are shown in the drawing and explained in more detail below. Show it

Fig. 1

a prepared and partially assembled single-wire connection of the cable connection in cast resin technology for the assembly;

Fig. 2

in partial sectional view an inner sleeve over the connector of a single wire for a cast resin molded shell;

Fig. 3

a fully assembled cable connection with four single wires in a cast resin molded shell for casting with a curable insulating material;

Fig. 4

a connection of three single wires prepared and partially assembled for assembly using shrink technology;

Fig. 5

in partial section representation the details of an inner sleeve on the connector of a single wire for a shrink sleeve;

Fig. 6

in partial section a cable connection with several single wires as shrunk and ready-to-use shrink sleeve.

The assembly of a fire-resistant cable connection according to the invention in casting resin technology is carried out in the following steps executed:

The outer sheaths 1 of the cables to be connected are in one Way removed as this is mostly from the assembly instructions the socket manufacturer is specified. Be on it the single wires 8 are bent open to free space for assembly work to create as per the illustration according to Fig. 1 can be seen. Then the single wires stripped. On each of the single wires to be connected an inner insulating tube 2 applied in a so-called "parking position", and then the individual conductors 13 by means of the provided connector 5 - in Fig. 1 to 3 as a press connector chosen - electrically connected to each other then the inner insulating tubes 2 in the middle of the Connectors can be pushed, as can be seen from Fig. 2 is.

Now the annular cavity between the inner insulating tube 2 and the wire insulation 8 at both ends with a Sealing mechanism 11 are closed. This prevents that between the insulation tube ends and the wire insulation before curing the insulating material in this cavity penetrates and flows under the insulating pipes; thereby it is avoided that a large mechanical Load on the area of the connection of the single wires is exercised.

After all inner insulating tubes 2 are sealed in this way are, the cast resin molded shell 12 around the Cable connection point laid around, fastened and sealed, so that they are potted with the curable insulating material can be. After the curing time has expired, it is fire-resistant Cable connection can be loaded electrically and mechanically.

When using the shrink technique is during assembly a fire-resistant cable connection according to the invention proceed as follows:

Equally as with the casting resin technology must Preparation stripped the cable ends to be connected, exposed and bent open, so that the outer Insulating tube 9 and the outer shrink tube 6 one of the cable ends can be pushed open like this 4 can be seen.

Advantageously, according to this shown in Fig. 4 Embodiment the connection points of the single wires 8 can be arranged longitudinally offset from each other. Thereon is one for each individual wire 8 to be connected inner insulating tube 2 and an inner shrink tube 3 in a "parking position" is spent, and then the single ladder 13 by means of their connectors 5 in a known manner be electrically connected.

Then the inner shrink sleeves 4 by means of a Heat source shrunk over the connector 5 so that the Shrink sleeves 4 double-sided insulation of the single wires cover sufficiently. According to the invention can advantageously a fire-resistant over these shrink sleeves 4 Tape wrap 10, e.g. be applied from mica tape. Then the inner insulating tubes 2 over the Shrink sleeves 4 cover these sufficiently on both ends pushed and then the outer insulating tube 9 over the entire connection area positioned that all inner sleeves are evenly covered on both sides.

Finally, the outer shrink tube is shrunk 9 such that the outer insulating tube on both sides is evenly covered and a tight connection between the outer shrink tube 9 and the outer jacket 1 is reached. Are only low mechanical loads the cable connection is also expected in the event of fire, can, also to create a particularly slim cable connection, on the use of the outer insulating tube to be dispensed with.

Claims (12)

1. Electrical cable join for single- or multi-wire power and control cables in which the electrically insulating and sealing sheath consists of a cast resin or shrink sleeve (12, 9) and in which the wires (8) in the area of the connector (5) are enclosed by shape-retaining sheathing (2) and the latter by the outer sheathing that covers the wire insulation (1),
   characterised in that

   over each electrical wire join, in addition to the protection that insulates electrically and against moisture, there are electrically insulating,

   moisture-repellent, high temperature-resistant and therefore fireproof moulded components (2), which retain their shape in the heat, as sheathing for the individual wire joins(5), which are permanently spaced by heat-resistant spacers.
2. Cable join according to claim 1, characterised in that the shape-retaining moulded component (2) consists of refractory ceramics or of a high temperature-resistant quartz glass or translucent fused quartz.
3. Cable join according to claims 1 and 2, characterised in that the shape-retaining, fireproof moulded component (2) is formed from moulded parts that are hollow inside as sheathing for each individual wire join.
4. Cable join according to claim 3, characterised in that the moulded parts that are hollow inside are preferentially tubes.
5. Cable join according to claims 1 and 2, characterised in that for the permanent spacing of the wire joins (8, 5), there are heat-resistant moulded parts with a cross-section shaped like a multi-pointed star or similar to a multiple U-profile.
6. Cable join according to one of the above claims characterised in that the individual wire joins (5) are offset against one another along the cable axes.
7. Cable join made by the cast resin method according to claims 1 and 2 characterised in that the shape-retaining and fireproof moulded components (2) that are slid over the electrical wire joins (5) are sealed against the wire insulations (8) by a sealing mastic (11).
8. Cable join produced by the cast resin method according to claim 7 characterised in that the inner sleeves consisting of an electrical connection (5) and the shape-retaining, fireproof moulded components (2), which are sealed against the wire insulations (8), are distanced from one another by heat-resistant moulded parts.
9. Cable join produced by the shrink method according to one of the claims 1 to 6 characterised in that the outer (6, 7) and the inner (3, 4) shrink tubes are treated with a flame-proofing agent and coated on the inside with a sealing compound, preferentially a hot-melt adhesive.
10. Cable join made by the shrink method according to claim 9 characterised in that the shrink sheathing (9) of all wire joins (5) is a moulded part with a hollow cross-section.
11. Cable join according to claim 10 characterised in that the inner shrink tubes (4) extend over the insulation (8) of the individual conductors (13) and are completely enclosed by the shape-retaining and fireproof moulded components (2).
12. Cable join according to claim 9 characterised in that the connectors (5) of the individual conductors (8, 13) are covered by a tape wrap (10) consisting of a fireproof wrap, preferentially a mica tape wrap, which is applied up to the wire insulations on both sides.

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